DE102016014066B3 - Gear shift for an electric motor bicycle auxiliary drive - Google Patents

Abstract

A gearshift (45) designed for the electromotive auxiliary drive (12) of a bicycle has a central shaft (40) in which the torque contributions of a crankshaft (14) and a drive shaft (35) are superimposed on one another. The central shaft (40), per gear stage via a pinion (43) and a drive wheel meshing therewith (26), with a Zugmittelrad (28) in rotary connection. In the smallest of the gear stages, the pinion (43) is rotationally rigidly connected to the central shaft (40), in the other gear stages, the pinions (43) on the central shaft (40) are roller-mounted. From the second lowest of the gear stages is between the central shaft (40) and the associated pinion (43) a positive clutch (46) with a on the central shaft (40) non-rotatable jaw wheel (48.2) effective. The claw wheel (48.2), and thus the coupling (46), is reversible by means of a by a servo motor (50) rotatable switching shaft (54) via a shift fork (49) by moving along the central shaft (40). The shift fork (49) is transversely guided by a support column (51) parallel to the axes of the central shaft (40) and the selector shaft (54). The shift fork (49) engages in a thread-like link (52) in the lateral surface (53) of the switching shaft (54) and opposite in a along the front of the jaw wheel (48.2) circumferential groove (60). In the gear ratios below the highest, a freewheel (56) is installed in each case between the Zugmittelrad (28) and the drive wheels (26). To operate the drive (31) for the additional torque and the servomotor (50) for the gear change, a control circuit (58) is provided, which is acted upon in accordance with, inter alia, of the crankshaft (14) just upcoming torque.

Description

The invention relates to a designed for an electric motor bicycle auxiliary drive gearshift according to the preamble of claim 1.

Such equipped auxiliary drive is from the DE 10 2014 009 833 B4 known. On a ring gear of a planetary gear, the torque contributions are brought together by a crankshaft via the planet carrier, with the sun locked, and by a drive shaft via a spur gear. The ring gear drives a there equipped with a chainring as Zugmittelrad hollow shaft, which is mounted on the crankshaft. The ring gear is constantly via a freewheel with the hollow shaft in engagement. As a result, this drive is overhauled if and as long as the hollow shaft is driven faster by the ring gear via a parallel-connected gearbox. For this purpose, the input gear of this transmission is rotationally rigidly connected to the ring gear by means of claws which are axially displaceable on the shaft of the planetary gear. How this gear shift is accomplished is not disclosed in the patent; also not, as it would be necessary apparatus-wise, in the interests of possible load jump-free, even pedaling the device described there to supplement other courses.

From the JP H10-194 186 A It is known to integrate an automatic multi-speed circuit in the dependent on the introduced pedal torque controlled electric motor auxiliary drive.

In recognition of the circumstances discussed above, the present invention has for its object to transmit the two superimposed torques structurally simpler on the gearshift and to interpret that it is functional in the interest of optimal power rating easily extendable to further grades beyond two, between those fully automatic switching is desirable.

This object is achieved by the interaction of the essential features specified in claim 1. Thereafter, the two torque contributions, if necessary via transmission, are introduced into a coupling wheel, which is in rotary connection with a central shaft. Apart from in any case in operation with the central shaft rotatably connected pinion of the lowest gear stage are mounted on the central shaft differently sized, meshing with drive wheels rotatably mounted, preferably roller bearings. For reversible clutch engagement, the pinion with the central shaft via coupling wheels, preferably designed as axially movable claw wheels, coupled, which in turn are in rotary connection with the central shaft or can be brought.

For such an axial displacement of the clutch wheels or the pinion, an electromagnetically initiated longitudinal stroke may be considered; However, it is preferably provided that a servomotor rotates a thread-like manner with a large pitch coiled backdrop in the lateral surface of a switching shaft by a limited angle, which engages, for example, a shift fork with a bolt. In addition, such a shift fork is bounded according to a u-geometry, in which the axially displaceable clutch wheel - or directly for the reversible clutch engagement axially displaceable pinion - the u-legs with a circumferential groove axially overlapping, rotates with the central shaft.

An extension of such kompaktbauenden and reliable operation, electric motor actuated automatic gearshift on other grades is readily possible that additional pinion-drive-wheel pairings of different translations, possibly together with clutch wheels, axially offset from each other on the central shaft or on the hollow shaft are lined up with associated scenes course in the switching shaft. By freewheels causes only the currently fastest rotating pinion transmits a torque on the meshing with him drive wheel on the hollow shaft to Zugmittelrad, the lower gears are each overtaken by the next higher. An additional freewheel on the hollow shaft may be provided for the reverse rotation of Zugmittelrades.

Thus, by merely driving the servomotor to rotate the shift shaft with the link for the clutch engagement, a pinion meshing with a drive gear can be coupled to the central shaft to drive the hollow shaft with the traction wheel in this current gear ratio. The control of the servomotor is fully automatic in accordance with the, from a built-in the surrounding housing of the auxiliary drive measuring device, currently determined operating values for in particular the torque and / or the cadence at the pedal. For this lack of external actuators and sensors no cables leave the enclosure, which prevents damage and incorrect settings. Fully automatic, the necessary additional torque from the electric motor drive and the optimum gear ratio for not unnecessarily fast pedaling is determined via a subsequent control circuit for the instantaneous power requirement, as it is known as such from the Pedelec measured value processing; and - even under load, so without having to adjust the pedaling or even temporarily interrupting - is changed to the appropriate gear.

Additional refinements and modifications of the solution according to the invention will become apparent from the other claims and, also taking into account the advantages thereof, from the following description of an outlined under abstraction on the functional essential preferred implementation example of this invention. The single FIGURE of the drawing shows a three-speed circuit for an electric motor bicycle auxiliary drive with a simplified representation of the torque superposition and pivoted in the Darstellebene sketched shift transmission.

A stable housing 11 the electromotive auxiliary drive 12 takes over, as on a bicycle frame (not shown), the inclusion of a bottom bracket 13 for the two-sided from the surrounding housing 11 protruding crankshaft 14 with their pedals (not shown) to the muscle drive of the bicycle.

The speed of the crankshaft 14 , which rotatably with a spur gear 16 equipped, is by means of a transmission gear 15 increased. That drives a coupling wheel 25 along with its central shaft 40 at. If it is the transmission 15 is a planetary gear, then preferably is the ring gear with the spur gear 16 engaged while the sun with the coupling wheel 25 and the central shaft 40 coaxial in rigid rotary connection. The planet carrier of this planetary gear is then preferably stopped by a support arm, acting on a fixed housing torque measuring device 42 ,

The enclosure 11 also houses a preferably high-speed electric motor drive 31 , Its speed is required by means of a reduction gear 32 reduced. This may in particular be a helical gear, or a transmission with a traction means such as a chain, a toothed belt or a profiled belt. Also a planetary gear with directly on the drive shaft 35 of the motor 31 sitting sun can be part of this reduction gear 32 be.

Both gears 15 . 32 So also designed with different gear stages or combinations, the output side are in engagement with the coupling wheel 25 ; so here's the torque contributions from the crankshaft 14 and from the drive shaft 35 each other for turning the central shaft 40 be superimposed.

The central shaft 40 is with a spur pinion 43 rotatably equipped. As this pinion ( 43 ) can basically also the coupling wheel 25 serve; especially if it is designed as a planetary sun, leaving only one of the gears 15 . 32 with the spur toothing of the coupling wheel 25 combs. In the interests of a clearer description of the invention, however, the following is sketched at the point as outlined by a separate, the coupling wheel 25 against axially offset pinion 43 gone out, that - like the coupling wheel 25 - non-rotatable with the central shaft 40 connected or can be connected to the operation.

In the first gear, the torque transmission from the coupling wheel 25 on a Zugmittelrad 28 combs a pinion 43.1 comparatively small diameter with a large drive wheel 26.1 , with which a hollow shaft 27 is equipped. The hollow shaft 27 is by rolling bearings 44 concentric on the crankshaft 14 stored. Axial against the drive wheel 26 is displaced on the hollow shaft 27 the mentioned Zugmittelrad 28 arranged rotationally fixed. This is used in a conventional manner, the drive of the surrounding housing 11 opposite to the bicycle frame mounted rear wheel (not shown) via a traction device 29 , for example via a chain, a toothed belt or a profile belt.

In that regard, a changeable translation between central shaft 40 and hollow shaft 27 is present, this is a gear shift 45 , Since their first gear is not the largest, is between the drive wheel 26.1 and its hollow shaft 27 a freewheel 56 intended.

For the second gear with its higher spur gear ratio is a second pinion 43.2 in engagement with another drive wheel 26.2 , If this second gear is the highest gear of this gearshift 45 are the hollow shaft 27 and the drive wheel 26.2 rotatably connected during operation. Otherwise it lies between the drive wheel 26.2 and its hollow shaft 27 also a freewheel 56 ,

This further, second pinion 43.2 rests by means of a rolling bearing 61 on the central shaft 40 , It is therefore not in rotary connection with the central shaft 40 but it can - if not the pinion itself is axially displaceable - by means of a coupling wheel, such as a claw wheel 48.2 , rotatably attached to them (and also separated from it again); what is referred to below as Umsteuern the clutch engagement.

Such a claw wheel 48.2 is along the central shaft 40 axially displaceable, but rotates with this. In front of an axial end face, the claw wheel preferably used here has 48.2 axially parallel claws 47 on. For the axial displacement, to form-fitting engagement in the axially adjacent pinion 43 , is a radial to the central shaft 40 extending shift fork 49 intended. Their u-like bordered fork opening (not shown) centripetally engages in a groove 60 one, around the claw wheel 48.2 runs along the forehead. In contrast, the shift fork protrudes 49 with a bolt 59 in a thread-like in the lateral surface 53 a reasonably thick shift shaft 54 running backdrop 52 one. For reversing between engagement and disengagement of the clutch claws 47 is the shift fork 49 by means of a servomotor 50 if necessary with reduction gear 57 , along the central shaft 40 slidable by a comparatively small stroke by the servomotor 50 , also reversible, the selector shaft 54 twisted in accordance with the setting slope by a small, sufficient for the clutch stroke angle. This axis-parallel coupling movement of the shift fork 49 becomes along one to the central shaft 40 and the shift shaft 54 parallel, housing-fixed support column 51 guided. Depending on the direction of rotation of the selector shaft 54 become the claws 47 of the claw wheel 48.2 with the associated, adjacent pinion 43 engaged thereby rotatably with the central shaft 40 connected, or disengaged again.

This way is with the wheel pairing 43.2 - 26.2 the second gear of the gearshift 45 enableable. For the third gear is a third pair of wheels 43.3 - 26.3 with own backdrop 52.3 for the axial displacement of a claw wheel 48.3 intended. In the shift shaft 54 is its backdrop 52.3 in the circumferential direction relative to the other backdrop 52.2 rotating angularly offset; the scenery 52.3 is therefore effective only when the shift shaft 54 from the servomotor 50 is rotated further by a certain angle of rotation. This can at the same time, as a result of opposing inclinations of the scenes 52.2 / 52.3 , the clutch engagement of the claw wheel 48.2 be opened again. In order to reduce the number of coupling movements, but this intervention is conveniently maintained. Then the slower, with a freewheel 56 provided second gear from the faster third gear overrun; until the slower reaches again.

The rotation of the switching shaft 54 with their axially offset helical scenes 52 for coupling or releasing the clutch claws 47 with the wheels 43 takes place by means of the reversible servomotor 50 over a strongly reducing gear 57 , to increase torque and there the scenes 52 only over a limited circumferential angle on the lateral surface 53 the switching shaft 54 extend. The corresponding control of the servomotor 50 takes place from a, also its torque contribution of the drive 31 retrieving, central, into the enclosure 11 integrated control circuit 58 according to an evaluation of the measuring plant 42 detected torque curve on the crankshaft 14 in order always to pedal with the same muscular performance at an adapted, therefore pleasant cadence.

One for the electromotive auxiliary drive 12 a bicycle designed gearshift 45 Thus, according to the invention has a central shaft 40 on, at which the torque contributions of a crankshaft 14 and a drive shaft 35 superimposed on each other; being the central shaft 40 , per gear stage via a pinion 43 and a drive wheel meshing therewith 26 , with a traction wheel 28 is in rotary connection or can be moved. In the smallest of the gears of this gearshift 45 , so in first gear, is the pinion 43 torsionally rigid with the central shaft 40 connected, in the other, higher gear stages are their pinions 43 on the central shaft 40 roller bearings. From the second lowest, so the second of the gears is between the central shaft 40 and the associated pinion 43 a positive coupling 46 with a coupling wheel, preferably in the form of one on the central shaft 40 non-rotatable but axially displaceable claw wheel 48.2 , effective. The claw wheel 48.2 So the clutch 46 , is preferably by means of one of a servomotor 50 rotatable shaft 54 via a shift fork 49 by moving along the central shaft 40 reversible. The shift fork 49 is doing so from one to the axes of the central shaft 40 and the shift shaft 54 parallel support column 51 led across. The shift fork 49 engages for reversing the clutch 46 in a thread-like backdrop 52 in the lateral surface 53 the switching shaft 54 and also in one along the forehead of the claw wheel 48.2 circumferential groove 60 one. Except in the highest gear is between each with the Zugmittelrad 28 equipped shaft and the drive wheels 26 a freewheel 56 built-in. As a result of the currently fastest of the gears are the slower overclocked. When the speed drops, the next slow gear step, even under load, takes over the drive of the traction means wheel 28 , For operating the additional drive 31 and the gear change servomotor 50 is a control circuit 58 provided in accordance with the current operating values, in particular that of the crankshaft 14 currently pending torque, but also about it derivable operating values such as the cadence or the driving speed, is acted upon. For this automatic gearshift 45 are therefore no sensors or controls outside the enclosure 11 required.

LIST OF REFERENCE NUMBERS

11

Enclosure (for 12 )

12

Auxiliary drive (with 31 )

13

Bottom bracket (for 14 in 11 )

14

Crankshaft (by 13 - 13 / 11 therethrough)

15

Transmission gear (for 14 )

16

Spur gear (at 14 )

17

18

19

20

21

22

23

24

25

Coupling wheel (on 40 )

26, 26.i

Driving wheels (at 27 ; between 43 and 27 / 28 ): i = 1, 2, 3

27

Hollow shaft (above 14 )

28

Traction wheel (at 27 )

29

Traction means (over 28 )

30

31

Drive (from 12 )

32

Reduction gearbox (for 31 )

33

34

35

Drive shaft (from 31 )

36

37

38

39

40

Central shaft (with 25 )

41

42

Measuring mechanism (in 11 For 14 )

43, 43.i

Pinion (between 40 and 26 ); i = 1, 2, 3

44

Rolling bearings (between 27 and 14 )

45

Gear shift (between 40 and 27 - 28 )

46

Clutch (between 40 and 43 . 26 . 27 . 28 )

47

Claws (on 48.i , for intervention in 43 )

48, 48.i

Clawwheels (between 40 and 43 ); i = 2, 3

49

Shift fork (between 54 and 48.i )

50

Servomotor (for 54 )

51

Support column (on 11 parallel 40 / 58 )

52, 52.i

Scenes (in 53 / 54 For 49 / 59 ); i = 2, 3

53

Lateral surface (from 54 , With 52 )

54

Shift shaft (for 49 )

55

56

Freewheel (between 27 and 26 )

57

Transmission (from 50 )

58

Control circuit (behind 42 , For 31 and 50 )

59

Bolt (on 49 for intervention in 52 )

60

Groove (on 48.i circulating, for the intervention of 49 )

61

Rolling bearings (between 40 and 43 )

Claims (10)

Gear shift ( 45 ), designed for an electric motor bicycle auxiliary drive ( 12 ), in which the torque contributions of a crankshaft ( 14 ) and a drive shaft ( 35 ) superimposed on one Zugmittelrad ( 28 ), characterized in that one of the two torque contributions acted upon central shaft ( 40 ) for more than one gear step coaxial with more than one pinion ( 43 ), which in each case via a meshing drive wheel ( 26 ) with the Zugmittelrad ( 28 ) is in rotational connection, wherein in a relation to the lowest gear stage higher gear stage between the central shaft ( 40 ) and the gear assigned to this gear, on the central shaft ( 40 ) mounted pinion ( 43 ) a reversible clutch engagement is provided. Gear shift according to claim 1, characterized in that the clutch engagement by means of a link ( 52 ) in a rotatable shaft ( 54 ) is reversible. Gearshift according to the preceding claim, characterized by one of a servomotor ( 50 ) rotatable shaft ( 54 ) for the reversible clutch engagement. Gear shift according to one of the two preceding claims, characterized in that a shift fork ( 49 ), transversely guided from one to the axes of the central shaft ( 40 ) and the shift shaft ( 54 ) parallel support column ( 51 ), on the one hand into the scenery ( 52 ) in a lateral surface ( 53 ) of the switching shaft ( 54 ) and on the other hand in a along the front of a clutch wheel encircling groove ( 60 ) intervenes. Gear shift according to one of the preceding claims, characterized in that a positive-locking clutch ( 46 ) with one, with the central shaft ( 40 ) in rotary connection, as a claw wheel ( 48.2 ) designed clutch wheel is provided. Gearshift according to the preceding claim, characterized in that the coupling wheel with axially parallel claws ( 47 ) to engage in the pinion ( 43 ) which is arranged on the central shaft ( 40 ) is stored. Gearshift according to one of the preceding claims, characterized in that - except in the highest gear stage - between one with the Zugmittelrad ( 28 ) equipped shaft and the drive wheel ( 26 ) a freewheel ( 56 ) is provided. Gearshift according to one of the preceding claims, characterized by a on the crankshaft ( 14 ) roller bearing hollow shaft ( 27 ) between the traction wheel ( 28 ) and the thus coaxial, axially staggered Triebrädern ( 26 ). Gearshift according to one of the preceding claims, characterized in that it is designed at least two-speed, wherein of the pinions ( 45 ) Only that of the smallest gear clutchless rotatably with the central shaft ( 40 ) is connected or connectable and whereby only the drive wheel ( 26 ) of the largest gear freewheeling rotation with the Zugmittelrad ( 28 ) is connected or connectable. Gear shift according to one of claims 3 to 9, characterized in that for operating the drive ( 31 ) and the servomotor ( 50 ) a control circuit ( 58 ) provided in accordance with that of the crankshaft ( 14 ) currently applied torque and possibly also derived therefrom operating values is acted upon.

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